JP3189719B2 - Manufacturing method of surface acoustic wave device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to relates to give Ru how suitably used in the manufacture of a surface acoustic wave device of constituting a plurality of surface acoustic wave filter element to the pressure conductive substrate.

[0002]

2. Description of the Related Art In recent years, a surface acoustic wave filter used in a communication device or the like has been used in which a plurality of surface acoustic wave elements are formed on the same piezoelectric substrate in order to obtain desired transmission characteristics. In this case, since the characteristics required for each surface acoustic wave element are different, the film thickness of the electrodes constituting the surface acoustic wave element is different between the surface acoustic wave elements.

Conventionally, the formation of surface acoustic wave elements having different electrode thicknesses on the same piezoelectric substrate has been performed through a process shown in FIG. The surface acoustic wave device obtained by the process shown in FIG. 4 is as shown in a sectional view in FIG. That is, the first surface acoustic wave filter element 41 formed using the electrode 41a having a relatively large thickness and the second surface acoustic wave filter element 42 having the electrode 42a having a relatively small thickness. , On the same piezoelectric substrate 43.

In forming the surface acoustic wave filter elements 41 and 42, first, as shown in FIG. 4A, a film thickness of an electrode 42a of the second surface acoustic wave filter element 42 is formed on a piezoelectric substrate 43. A conductive film 44 having an equal thickness is formed. The conductive film 44 is formed, for example, by evaporating aluminum or the like.

Next, a resist is applied to the entire surface of the conductive film 44 and then exposed using a mask,
The resist 45 is patterned as shown in FIG. The patterning of the resist 45 is performed so as to have the same shape as the electrodes of the first and second surface acoustic wave filter elements.

Next, by etching the conductive film 44 and removing the resist 45, the electrode 42a of the second surface acoustic wave filter element 42 is formed as shown in FIG. On the surface acoustic wave filter element 41 side, the electrode 41a formed by the thickness of the conductive film 44
'.

Next, as shown in FIG. 4 (c), the first surface acoustic wave filter element 41 has an electrode 41a '.
A resist 46 'is formed in a region where is not formed, and a resist 46 is applied to the second surface acoustic wave filter element 42 side. In this case, the resist 46
'Is formed by applying a resist on the entire surface of the piezoelectric substrate 43 and then patterning by photolithography, but it is necessary to accurately leave the resist 46' between the electrodes 41a 'formed in advance.

Thereafter, by depositing a conductive material such as Al, as shown in FIG.
The electrode 41a ″ is laminated thereon. In this case, the resist 46
The conductive film 47 is also formed on the resist 46 '.

Next, the resists 46 and 46 'are lifted off together with the conductive film 47 to form an electrode 41a shown in FIG.
To complete. Thus, electrodes 41a and 42a having different thicknesses of the surface acoustic wave filter elements 41 and 42 are formed.

[0010]

However, in the above-mentioned manufacturing method, a resist 46 'is formed between the first formed electrodes 41a', and the electrodes 4a are accurately formed on the electrodes 41a '.
1a "must be formed on the other hand. On the other hand, the electrode width of the surface acoustic wave element is very thin, about 1 .mu.m. Must be done in
There is a problem that the manufacturing yield is extremely deteriorated.

The present invention solves the above-mentioned drawbacks, and when forming a plurality of electronic component elements using electrodes having different thicknesses on the same substrate, it is possible to form each electrode accurately even with coarser accuracy. It is an object of the present invention to provide a method for manufacturing an electronic component capable of exhibiting desired characteristics.

[0012]

According to a first aspect of the present invention, there is provided a first surface acoustic wave filter having an IDT electrode on a piezoelectric substrate, and a second surface acoustic wave filter having an electrode thickness different from that of the first surface acoustic wave filter. in the method of forming a surface acoustic wave filter surface acoustic wave device of, on the piezoelectric substrate, and forming an IDT electrode of the first surface acoustic wave filter, the first surface acoustic wave IDT electrode of filter is shaped
On the formed piezoelectric substrate, the second surface acoustic wave filter
Of resist except for the area where the IDT electrode is formed
And an IDT electrode film of the second surface acoustic wave filter
Forming a conductive film having a thickness equal to the thickness,
And lift off the conductive film formed on the resist
Forming an IDT electrode of the second surface acoustic wave filter;
And a step .

[0013]

[0014]

[0015]

[0016]

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, non-limiting embodiments of the present invention will be described with reference to the drawings to clarify a method of manufacturing an electronic component and a method of manufacturing a surface acoustic wave device according to the present invention. .

(First Embodiment) FIG. 1 is a sectional view for explaining a method of manufacturing a surface acoustic wave device according to a first embodiment of the present invention.

In this embodiment, as shown in FIG. 1E, on the same piezoelectric substrate 3, a first surface acoustic wave filter element 1 and a second surface acoustic wave filter element 2 having different electrode film thicknesses. And are formed. The electrode 1a of the surface acoustic wave filter element 1 is relatively thicker than the electrode 2a of the surface acoustic wave filter element 2.

First, as shown in FIG. 1A, a conductive film 4 having the same thickness as the electrode 1a of the first surface acoustic wave filter element 1 is formed on the entire surface of the piezoelectric substrate 3. Piezoelectric substrate 3
Can be composed of a piezoelectric single crystal such as LiTaO ₃ , LiNbO ₃ or quartz, or a piezoelectric ceramic such as a lead zirconate titanate-based piezoelectric ceramic. Further, as the piezoelectric substrate 3, a substrate in which a piezoelectric thin film such as ZnO is formed on an insulating substrate made of an insulating material such as alumina may be used.

The conductive film 4 is formed by applying a conductive material such as Al by an appropriate method such as vapor deposition, sputtering, and plating. Next, a positive resist is applied on the entire surface of the conductive film 4. On this resist, the electrode 1a of the first surface acoustic wave filter element 1 is exposed using a mask, which is a shielding part, and then the exposed resist is removed to form a patterned resist. Get 5.

Next, the resist 5 is not affected, but the conductive film 4
Etching using an etchant that can remove
As shown in FIG. 1B, an electrode 1a is formed. next,
A positive resist is applied to the entire surface of the piezoelectric substrate 3, and then, on the second surface acoustic wave filter element 2 side,
A mask having an opening in the pattern shape portion of the electrode 2a is laminated on the resist and exposed, and the exposed resist of the electrode 2a is removed to obtain a patterned resist 6 '. Note that, as is clear from FIG. 1C, on the first surface acoustic wave filter element 1 side,
The electrode 6 is protected by the resist 6.

Next, a conductive film having a thickness equal to that of the second electrode 2a is applied. Thus, the second electrode 2a is formed as shown in FIG. Thereafter, the conductive film 7 provided on the resists 6, 6 'is removed.
'And lift-off to obtain the surface acoustic wave device 8 shown in FIG.

In the conventional method shown in FIG. 4, the resist 46 'must be accurately patterned under the previously formed electrode, and the electrode 41a "must be accurately formed on the previously formed electrode 41a'. However, in the present embodiment, it is not necessary to carry out a process requiring such an accuracy on the order of submicrons, that is, the patterning of the resist 5 and the resist 6 ′. In the patterning, it is sufficient if the electrodes 1a and 2a have a width of about 1 μm with an accuracy of at most several tens of microns, so that the surface acoustic wave device 8 exhibiting sufficient transmission characteristics can have a high yield rate. Can be manufactured to carry.

(Second Embodiment) FIG. 2 is a sectional view for explaining a method of manufacturing a surface acoustic wave device according to a second embodiment of the present invention. Also in this embodiment, as in the first embodiment, and as shown in FIG. 2D, the first and second surface acoustic wave filter elements 11 and 12 having different electrode film thicknesses have the same piezoelectric substrate. 13 is formed on the surface acoustic wave device. The electrode 11a of the surface acoustic wave filter element 11 is thicker than the electrode 12a of the surface acoustic wave filter element 12.

First, a conductive film 14 is formed on the piezoelectric substrate 13. The steps and materials for forming the conductive film 14 on the piezoelectric substrate 13 can be performed in the same manner as in the step of forming the conductive film 4 on the piezoelectric substrate 3 in the first embodiment. Next, the first
On the surface acoustic wave filter element 11 side, the conductive film 14
A positive resist 15 is provided thereon. The application of the resist 15 is performed by the first and second surface acoustic wave filter elements 11 and 1.
2 may be performed with an accuracy that can be separated.

Next, the second surface acoustic wave filter element 12
On the side, the conductive film 14 is half-etched. Half etching does not attack the resist 15, but
This is performed using an etchant capable of etching the conductive film 14,
And it is performed so that the thickness may be finally equal to that of the second electrode 12a.

Thereafter, by removing the resist 15, a conductive film 14a and a half-etched conductive film 14b are formed as shown in FIG. 2B.

Next, a positive resist is applied to the entire surface of the conductive films 14a and 14b, and thereafter, a mask having openings other than the patterns of the first and second electrodes 11a and 12a is laminated on the resist. Then, by exposing and removing the exposed resist portions, patterned resists 16a and 16b shown in FIG. 2C are obtained. Resist 16a
Are patterned according to the shape of the first electrode 11a, and the resist 16b is patterned according to the shape of the second electrode 12a.

Next, the conductive film 14a and the half-etched conductive film 1, which do not attack the resists 16a and 16b,
Etching using an etchant capable of etching 4b,
After that, the resists 16a and 16b are removed. Thus, the surface acoustic wave filter device 1 shown in FIG.
7 is obtained.

Also in this embodiment, the resist 15 is applied only by half-etching and patterning to obtain the resists 16a and 16b. Therefore, these steps can be performed with an accuracy of at most several tens of microns. As in the case of the first embodiment, it is possible to manufacture a surface acoustic wave device having a high yield rate and exhibiting good transmission characteristics.

(Third Embodiment) FIG. 3 is a cross-sectional view for explaining a third embodiment applied to a method of manufacturing a surface acoustic wave device. In this embodiment, FIG. As shown in (1), a surface acoustic wave device in which first and second surface acoustic wave filter elements 21 and 22 having different electrode thicknesses are formed on the same piezoelectric substrate 23 is manufactured.

First, as shown in FIG. 3A, a conductive film 24 having a thickness equal to the thickness of the first electrode 21a is formed on the piezoelectric substrate 23. The steps of forming the conductive film 24 on the piezoelectric substrate 23 and these materials can be performed in the same steps as in the first embodiment.

Next, a positive resist is applied to the entire surface of the conductive film 24, and thereafter, the first and second electrodes 21a and 21a are formed.
A mask having a portion 22a as a shielding portion is overlapped, exposed, and the exposed resist portion is removed to obtain a patterned resist 25. The resist 25 is composed of the first
It is provided at a portion where the second electrodes 21a and 22a are located.

Next, etching is performed using an etchant that does not attack the resist 25 but can etch the conductive film 24, and the resist 25 is further removed. In this way,
As shown in FIG. 3B, an electrode 21a is formed, and a thick electrode 22a 'is formed on the second surface acoustic wave filter element 22 side.

Next, as shown in FIG. 3C, a resist 26 is provided on the first surface acoustic wave filter element 21 so as to protect the electrode 21a. The application of the resist 26 is performed by the first and second surface acoustic wave filter elements 21 and
Since it can be performed with the accuracy of separating the two, it can be performed with an accuracy of at most several tens of microns.

Next, half etching is performed so that the thickness of the electrode 22a 'becomes the final thickness of the second electrode 22a. In this way, as shown in FIG.
Is completed.

Thereafter, by removing the resist 26, the surface acoustic wave device 27 shown in FIG. 3E can be obtained. Also in the third embodiment, the application of the resist 26 does not need to be performed with high precision, so that a surface acoustic wave device having sufficient transmission characteristics can be provided while increasing the yield rate.

(Modification) In the first to third embodiments, either a negative resist or a positive resist may be used as the resist, and a mask may be prepared according to the type of the resist.

[0040]

In addition to the first and second electronic component elements, the present invention can be applied to a method of manufacturing an electronic component in which another electronic component element is formed on the same substrate.

[0042]

According to the first aspect of the present invention, after the electrodes of the first electronic component element are formed on the substrate, the electrodes of the first electronic component element are protected on the same substrate by a resist. Since the electrodes of the second electronic component element are formed by photolithography and etching, the first
In the formation of the electrode of the electronic component element and the formation of the electrode of the second electronic component element, it is not necessary to carry out a step requiring higher accuracy as in the conventional method. For example, when the method is applied to a method for manufacturing a surface acoustic wave device as described in claim 5, the width of the electrode is very narrow, about 1 μm, but even in this case, the accuracy is at most about tens of μm. Therefore, it is possible to significantly increase the yield rate of non-defective products in manufacturing.

According to a second aspect of the present invention, in the method of manufacturing an electronic component according to the first aspect, the step of forming an electrode of the second electronic component element includes the step of forming an electrode of the second electronic component element. After applying a resist except for the region to be formed, forming a conductive film having a thickness equal to the electrode thickness of the second electronic component element, only lifting off the resist and the conductive film formed on the resist, An electronic component having first and second electronic component elements having different film thicknesses can be reliably obtained. That is, since the application of the resist, the formation of the conductive film, and the lift-off of the resist and the conductive film formed on the resist do not require very high precision, the yield of non-defective products in the production of electronic components can be effectively increased. obtain.

According to the third aspect of the present invention, the first substrate is provided on the substrate.
Forming a conductive film having a thickness equal to the electrode film thickness of the electronic component element, applying a resist on a region where the first electronic component element is formed, and forming a conductive film in a region where the second electronic component element is formed Is half-etched to have a thickness equal to the electrode thickness of the second electronic component element, and the conductive film and the half-etched conductive film are formed by photolithography so as to have the electrode shape of the first and second electronic component elements. In addition, since it is only necessary to perform patterning by etching, it is not necessary to carry out a step requiring extremely high accuracy, as in the case of the first aspect of the present invention. Therefore, for example, when the present invention is applied to the manufacture of a surface acoustic wave device having an electrode width of about 1 μm, the accuracy in each step is several tens μm.
Since it is sufficient, the non-defective rate at the time of manufacturing can be effectively increased.

According to the fourth aspect of the present invention, the first,
The electrode of the second electronic component is formed so as to have a thickness equal to the electrode thickness of the first electronic component, the first electronic component is protected on the resist, and the second electronic component is protected. Since the electrode of the second electronic component element is formed by half-etching the electrode of the element, it is possible to perform a process requiring extremely high accuracy, similarly to the first and third aspects of the invention. Good. Therefore, similarly, the non-defective rate of the electronic component can be greatly increased. For example, when applied to the manufacture of a surface acoustic wave device as described in claim 5, when the electrode width is as thin as about 1 μm. However, since the accuracy required in each of the above steps is at most about several tens of μm, the yield of the surface acoustic wave device can be greatly increased.

According to the invention set forth in claim 5, according to claim 1,
By using each of the manufacturing methods described in (1) to (4), a very thin surface acoustic wave device having an electrode width of about 1 μm can be manufactured at a high yield rate. Therefore, a surface acoustic wave device having good transmission characteristics can be provided at low cost.

[Brief description of the drawings]

FIGS. 1A to 1E are cross-sectional views illustrating a manufacturing method according to a first embodiment of the present invention.

FIGS. 2A to 2D are cross-sectional views illustrating a method for manufacturing an electronic component according to a second embodiment of the present invention.

FIGS. 3A to 3E are cross-sectional views illustrating a method for manufacturing a surface acoustic wave device according to a third embodiment of the present invention.

FIGS. 4A to 4E are cross-sectional views illustrating a method for manufacturing a conventional surface acoustic wave device.

[Explanation of symbols]

 1, 2 ... first and second surface acoustic wave filter elements 1a, 2a ... first and second electrodes 3 ... piezoelectric substrate 4 ... conductive film 5 ... resist 6, 6 '... resist 7 ... conductive film 8 ... elasticity Surface acoustic wave devices 11, 12: first and second surface acoustic wave filter elements 11a, 12a: first and second electrodes 13: piezoelectric substrate 14: conductive film 14a: conductive film 14b: half-etched conductive film 15 ... Resist 16a, 16b ... Resist 17 ... Surface acoustic wave device 21, 22 ... First and second surface acoustic wave filter elements 21a, 22a ... First and second electrodes 23 ... Piezoelectric substrate 24 ... Conductive film 25 ... Resist 26 resist 27 surface acoustic wave device

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H03H 3/00-3/10 H03H 9/145 H03H 9/64

Claims (1)

(57) [Claims] 1. A surface acoustic wave formed by forming a first surface acoustic wave filter having an IDT electrode on a piezoelectric substrate, and a second surface acoustic wave filter having a different electrode thickness from the first surface acoustic wave filter. In the method for manufacturing a wave device, the first surface acoustic wave filter may be provided on the piezoelectric substrate.
Forming a DT electrode; and forming an IDT electrode of the first surface acoustic wave filter.
ID of the second surface acoustic wave filter on the piezoelectric substrate
Applying resist except for the region where the T electrode is formed
And a film thickness equal to the IDT electrode film thickness of the second surface acoustic wave filter.
Forming a thick conductive film, and removing the resist and the conductive film formed on the resist;
IDT electrode of the second surface acoustic wave filter
Forming a surface acoustic wave device.